The present invention relates to a golf club head, more particularly to a backside structure capable of making the center of gravity of the club head lower and deeper and improving the restitution coefficient of the clubface.
It has been known in the art that lowering the sweet spot is preferable for the average golfers because the balls become liable to hit above the sweet spot, and the ball lunching angle is increased and at the same time the backspin is lessened, and as a result, the traveling distance of the ball is increased. Further, making the center of gravity deeper is also preferable because the directionality may be improved.
On the other hand, Japanese patent No. 2130519 (corresponding to U.S. Pat. No. 4,928,965) teaches improving the restitution coefficient of the clubface by matching the clubface with the golf balls with respect to the frequency at which the mechanical impedance in the primary mode vibration becomes minimum.
Indeed, the frequency of the clubface can be adjusted by changing the material of the face plate, the thickness of the material, the thickness distribution, heat treatment (in case of metal) and the like. However, the adjustment, especially fine adjustment is rather difficult. Further, adjustments on the finished club heads are almost impossible.